Cast failure and error results

src/spectator/formatters/default_formatter.cr

@@ -30,7 +30,7 @@ module Spectator::Formatters
         puts "Failures:"
         puts
         failures.each_with_index do |failure, index|
-          display_failure(failure.as(FailedResult), index + 1)
+          display_failure(failure, index + 1)
         end
       end
     end

src/spectator/report.cr

@@ -28,7 +28,7 @@ module Spectator
 
     # Returns a set of results for all failed examples.
     def failures
-      @results.select(&.failed?)
+      @results.select(&.failed?).map(&.as(FailedResult))
     end
 
     # Number of examples that had errors.
@@ -38,7 +38,7 @@ module Spectator
 
     # Returns a set of results for all errored examples.
     def errors
-      @results.select(&.errored?)
+      @results.select(&.errored?).map(&.as(ErroredResult))
     end
 
     # Number of pending examples.